/*
 * Copyright (c) 2004-2006 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Gou Pengfei
 * Date:    April. 2011
 */

#ifndef __CPU_EDGE_BASE_EXIT_PREDICTOR_HH__
#define __CPU_EDGE_BASE_EXIT_PREDICTOR_HH__

#include "base/types.hh"
#include "base/misc.hh"
#include "config/the_isa.hh"
#include "arch/isa_traits.hh"
#include "params/DerivEdgeCPU.hh"
#include "cpu/edge/pred/base_predictor.hh"
//#include "cpu/edge/pred/predictor_table.hh"

/**
 * This class provide some common interfaces, such as lookup,
 * update and squash, for exit predictors.
 * */
template<class Impl>
class BaseExitPredictor : public BasePredictor<Impl>
{
  public:
    typedef TheISA::BlockID BlockID;
    typedef TheISA::ExitID ExitID;

    enum PredictorType {
        Global,
        Local,
        TAGE,
        Tour,
        InvalidPredictionMode
    };

    PredictorType exit;

    const std::string _name;

    const std::string &name() const { return _name; }

    BaseExitPredictor(DerivEdgeCPUParams *params, std::string _exit) :
        BasePredictor<Impl>(params),
        _name(params->name + "." + _exit)
    {
        if (_exit == "Global") {
            exit = Global;
        } else if (_exit == "Local") {
            exit = Local;
        } else if (_exit == "TAGE") {
            exit = TAGE;
        } else if (_exit == "Tour") {
            exit = Tour;
        } else {
            exit = InvalidPredictionMode;
        }
    }

    virtual void regStats()
    {}

    virtual ~BaseExitPredictor()
    {}

    virtual void reset() = 0;

    /**
     * Looks up the given block address in the branch predictor and returns
     * an exit ID of the block.
     */
    virtual TheISA::ExitID lookup(BlockID block_id, BlockID oldest_block_id,
        Addr &block_addr, int addr_space_ID, ThreadID tid) = 0;   

    /**
     * Updates the branch predictor with the actual result of a branch.
     * Return the prediction before update.
     */
    virtual TheISA::ExitID update(BlockID block_id, Addr &block_addr,
            int addr_space_id, ExitID actual_exit_id,ThreadID tid) = 0;

    /**
     * Restores the branch history on a squash.
     */
    virtual void squash(BlockID block_id, Addr block_pc, ExitID exit_id,
            ThreadID tid) = 0;

    /**
     * Restores the branch history on a squash.
     */
    virtual void squash(BlockID block_id, ThreadID tid) = 0;

    /**
     * Get the counter bits for this predictor.
     * */
    virtual int getCounterBits() = 0;

    virtual uint64_t getPathHistory(ThreadID tid)
    { 
        panic("Unimplemented function: getPathHistory()\n");
        return 0; 
    }

    virtual uint64_t getPathHistory(BlockID block_id, ThreadID tid)
    { 
        panic("Unimplemented function: getPathHistory()\n");
        return 0;
    }

    virtual uint64_t getGlobalHistory(ThreadID tid) 
    {
        panic("Unimplemented function: getGlobalHistory()\n");
        return 0;
    }

    virtual uint64_t getGlobalHistory(BlockID block_id, ThreadID tid)
    {
        panic("Unimplemented function: getGlobalHistory()\n");
        return 0;
    }
};

#endif // __CPU_EDGE_BASE_EXIT_PREDICTOR_HH__
